Harald Szeemann’s mother did not approve of “When Attitudes Become Form.” A resident of Bern, Switzerland, where his famous exhibition took place in 1969, she was horrified by “Attitudes” and the controversy it caused. I’m getting all these terrible phone calls, she wrote to her son. You have to stop doing these gag exhibitions.

That letter from Mrs. Szeemann is one of many archival documents on view on the ground floor of the Ca’ Corner della Regina, the 18th-century Venetian palazzo where Germano Celant, curator of the Prada Foundation, has recreated Szeemann’s groundbreaking show, working in collaboration with the artist Thomas Demand and the architect Rem Koolhaas. This may not be the main event in town—that would be the biennale—but still it’s made an impact. On the second of three press preview days, people were lining up outside, bumping umbrellas in the rain.

Szeemann’s exhibition was revolutionary in that it brought together a set of then-disparate emergent American and European movements—Arte Povera (which Germano Celant was writing about at the time), Postminimalism, Conceptualism, and Land Art—and mixed all the work together, rather than arrange it according to the artists’ nationalities. Szeemann, who died in 2005, was the original globetrotting curator—interestingly, a small gallery here contains his high school notebooks, which speak to an early love of geography—now familiar to us from biennials the world over, and perhaps best exemplified these days in the person of Hans Ulrich Obrist. In retrospect, Szeemann’s achievement is all the more impressive in that he operated without the advantage of hyper-efficient international travel, never mind the internet. (A reality check on what has become the art world’s movable feast: 50,000 number people attended the five-day-long Art Basel Miami Beach last year; barely anyone, comparatively speaking, saw the original “When Attitudes Become Form.”)

Mr. Celant and his team have reproduced the floor plan of the Kunsthalle Bern’s 1918 building, down to the moldings, radiators and doors (though the occasional 18th-century Italian wall painting tends to disrupt suspension of disbelief) and meticulously placed each artwork, by the likes of Walter De Maria, Bruce Nauman, Sol LeWitt, Richard Serra, Joseph Beuys and Mario Merz, in the exact arrangement in which they were installed in 1969. Such an undertaking would not have been possible without extensive research into the Szeemann archive, which was housed in Bern until 2011, when it was acquired by the Getty Research Institute in Los Angeles, which had more room and a larger staff to undertake the mammoth task of organizing it. (With a team of 20, it will still take the Getty four to five years to process everything.)

“Szeemann kept his own system, and it was a dispersed system,” Getty Research Institute curator Glenn Phillips told The Observer at the Ca’ Corner on Thursday afternoon. “The material from ‘Attitudes’ was in 300 different locations within an archive that stretches a kilometer long. You can’t just go to the ‘Attitudes’ box.” Mr. Phillips, who calls the Szeemann archive “probably the greatest 20th-century art archive in the world,” happens to be a veteran of what he calls “exhibition remakes,” mostly ones involving performance art. The Prada Foundation show’s “detective work,” as Mr. Phillips put it, took the Getty—Mr. Phillips, along with a research assistant, five cataloguers, three conservators and four photographers—a year to complete. Installation photography had to be scrutinized. An Edward Kienholz piece that was in the original show was forgotten, Mr. Phillips said, because almost every photograph had a visitor’s head blocking the piece. They finally found one that showed it. A more speculative part of the Prada Foundation’s show is the Ca’ Corner della Regina’s fifth floor, which attempts to recreate the portion of “Attitudes” that took place in a schoolhouse across the street from the Kunsthalle. There was barely any documentation of that portion of the show, and the schoolhouse was recreated in an art version of CSI: researchers located and pored over photographs taken by people in Bern who had visited the show.

Displayed on the palazzo’s ground floor in glass cases are early drafts of Szeemann’s artist lists for the show, as well as his brainstorming for a title. And there are letters from artists like Mel Bochner, Richard Long and Giovanni Anselmo, outlining proposals for pieces and supplying sketched diagrams. Robert Barry’s letter describes his ephemeral contribution of sending uranyl nitrate into the air. I’m not in Bern, the letter reads, in part, so you’ll have to take the photograph of the work. Barry’s letter, like those of Douglas Huebler and Joseph Kosuth, is on the letterhead of art dealer Seth Siegelaub; it was partly from Siegelaub’s famous book of Xeroxes, which Szeemann saw in 1968, that Szeemann realized a book could also be an artwork, and 14 artworks in “Attitudes” took the form of pages in the original catalogue. Szeemann’s exhibition was notable for the close way in which he worked with artists, becoming a kind of co-creator, and for the fact that he included some lesser-known artists from places that were at that time, relatively speaking, off the art world’s grid. These letters reveal that he found some of them through artists he’d already chosen. Bruce Nauman, for instance, suggests that Szeemann look at some artists from the Bay Area conceptualists, like Paul Cotton in Berkeley.

Part of what was scandalous about the exhibition was that its installation ran counter to the rational ones most art viewers were used to. Artworks are positioned extremely close to one another, providing little room for visitors, and indeed at the Ca’ Corner, there are areas of the exhibition, narrow strips of floor between fragile artworks where, for preservation purposes, guards forbid visitors to enter.

But circulation was the mildest complaint back in 1969. A precise recreation of the show would have staged, outside, the protests Mrs. Szeemann complained to her son that she was seeing on television. Two Swiss artists burned their military uniforms in front of the Kunsthalle. A group of artists dumped 200 pounds of horse manure there and stuck a sign in it. These detractors’ voices are represented at the Ca’ Corner by newspaper cartoons. There’s one of Szeemann standing in front of a junk shop, apparently planning his next exhibition. There’s an artist saying, to a TV interviewer, “My normal artistic medium is dynamite.” There’s a garbage truck speeding away while a man shouts after it, “No! No! You’re taking away the show!” (This, and the horse manure gesture, were likely references to Reiner Ruthenbeck’s piece, a metal rod sticking out of a pile of ashes from the Bern incinerator; as far as certain commenters were concerned, Szeemann had brought the city’s trash into its museum.)

These documents are astounding today, and rather amusing, given the critical and market status most of the “Attitudes” artists have achieved in the intervening years, and the mythological position the exhibition has assumed in the art world’s collective consciousness. It would be difficult to overestimate the importance of Szeemann’s exhibition in the curatorial community, for instance. Jens Hoffmann, now deputy director at the Jewish Museum, recently curated an exhibition called “When Attitudes Became Form Become Attitudes.” Both an homage to the Szeeman show and an update, it included information and materials relating to the original, but was dominated by artists of today working in modes pioneered by the artists in “Attitudes.” “What I found out,” Mr. Hoffmann says in a video interview produced in conjunction with the show, “is that many of the artists who pick up on those historical artists and movements have a nostalgic longing for that period of the late ’60s…It represents a time when art was not tainted yet by the overpowering market…”

Nostalgia for this period isn’t limited to visual artists—after all, Mad Men is now just a year behind L’Année Attitudes. But watch two black-and-white films at the Prada, both of them made by journalists in 1969 just before the exhibition opened, when the artists were busy installing their work, and it’s easy to understand why even artists who didn’t experience the period have a kind of nostalgia for it. Here’s Lawrence Weiner, long-bearded even then, looking like the dock worker that he’d only recently been. His piece is, he’s removing a square of plaster from the wall. “That’s all,” he tells the journalist. “That’s it.” The journalist asks if he really thinks people don’t need art. “If you feel you don’t need it, you don’t need it,” he tells her. “I’m not going to force it on you, or try to convince you.” He takes a swig from his bottle of beer, a drag from his cigarette, and resumes chipping away at the plaster. Then there’s the earth artist Michael Heizer, who, emerging from a ditch in front of the Kunsthalle, is a dead ringer for James Dean. You were digging and now others are digging, the journalist says to him, having switched from her native French to English when he indicated he didn’t understand. Why? “I don’t like to work,” he tells her, smiling slyly. Why, she asks him, do you work in the West? “Je vie [sic] a New York,” he says, switching to French. “Il n’ya pas de terrain la.”

If you want to understand the extent to which these artists have attained institutional acceptance, consider that last year Mr. Heizer’s 340-ton granite boulder, Levitated Mass (2012), was transported from Riverside, Calif., to the Los Angeles County Museum of Art by a 196-wheel truck over an 11-day period, at a cost to the museum (paid by private donors) estimated at $10 million.

In an interview in the catalogue for the Prada Foundation exhibition, Germano Celant discusses the importance of recreating exhibitions like “Attitudes” so as to further enhance our understanding of artworks through seeing them, once again, in the environment in which they were first presented. Also important to him in this regard is revisiting the particular identity of a curator like Szeemann. But his recreation has ended up being significant for a reason he perhaps could not have anticipated. There is a kind of homage to Szeemann’s exhibition just down the Grand Canal from the Prada Foundation: the Venice Biennale. Prior to Szeemann’s transformative shows at Kunsthalle Bern, it was still primarily a place for Swiss artists. “You could help so many Bern painters with their careers, and instead you are dragging your name through the mud,” Mrs. Szeemann wrote to her son. Szeemann used his position of authority to change the conversation about art. In a not entirely dissimilar manner, Massimiliano Gioni has used the platform of the Biennale to relocate so-called outsider artists into the center of the conversation. Yes, he has included contemporary artists from all over the world, but he has also traveled into the past, and into realms (the art of soi-disant mystics, theosophers, the mentally ill) that many still insist on ghettoizing. The conversation into which Mr. Gioni is introducing these outsiders is, ultimately, the one originated by Szeemann.